No, the newer DMA scanners really don't lend themselves well to cut and paste operations (although you can...) - the reason is that you don't have banks in the traditional sense. You have to think in terms of systems, sites and groups - and that takes some doing if you've been doing it the other way for some time.
In addition the 15x is going to be somewhat limited if you're trying to hear the County system, as it has some digital talkgroups, which it won't be able to handle. Here is the link in our database - and note that anything in blue, both here and in our wiki, is a link
Montgomery County PA Trunking System, Various, Pennsylvania - Scanner Frequencies
Any talkgroup with a mode of 'D' is digital. Anything with an 'E' is encrypted - no scanner can decode these.
If you still want to pursue this, then we have a few references to help - all of what I am about to mention is found in the following article
Programming Your Uniden Scanner - The RadioReference Wiki
Regardless of what scanner you want to use, you need to connect it via USB if you're using a newer PC without any serial ports. Our Connecting Scanners via USB article discusses this in detail.
Next is understanding DMA and the scanner itself. We have a DMA FAQ, but even better would be the Easier to Read manual. Don't try to use the Uniden manual - and there's even a printed version of the XT Easier to Read series if you are better off with that.
Next FreeScan (which works with all the Uniden DMA Scanners) has a user guide - and in there, are the hints as to how to set up the scanner before making the connection (which happens to be the reference right out of the user guide).
I would take some time to do some reading first and see if this is the way you want to go
best regards..Mike